I'd like to add all these proxies and based on the suffix I would like for Vray Scatter to take HIGH that are close to camera, MEDIUM that are mid range, LOW that are far away. The idea is that the tree would be replaced by the same model but lower poly. So all scale/rotation etc etc would match. This way in animation cases we would get the littlest change.

Is it possible to get that implemented?

We have Camera distance decay thini. So Distance Far, Distance Near. If we only could add a Gradient, R_G_B, with R being High, G being Medium, B being Low. Then we can fine tune the way they blend as well as maybe add a noise so the blending line is bit mixed more. This way we could LOD entire scene very quickly and allow us for a greater control easy of use. Even without gradient we could live. Just give us ranges maybe ? High xx - xx/ med xx-xx/low xx-xx + roughness so they can penetrate or the ranges could overlap maybe?